Replace use of AccountGroup by an interface for various classes

Previously, GroupDescription.Internal served only as a marker for
internal groups and simply delegated to AccountGroup. By converting
GroupDescription.Internal to a real interface, we gain a lot of
flexibility. For instance, we are free to use another class to
represent internal groups (which will be necessary for the migration
of groups to NoteDb).

Change-Id: If7397898d8508184a2ccdc7c371ed60ada7d6f3e

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/rest/change/SuggestReviewersIT.java

@@ -25,19 +25,15 @@ import com.google.gerrit.acceptance.GerritConfig;
 import com.google.gerrit.acceptance.Sandboxed;
 import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.common.data.GlobalCapability;
-import com.google.gerrit.common.data.GroupDescription;
-import com.google.gerrit.common.data.GroupDescriptions;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.common.ChangeInput;
 import com.google.gerrit.extensions.common.GroupInfo;
 import com.google.gerrit.extensions.common.SuggestedReviewerInfo;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.group.CreateGroup;
-import com.google.gerrit.server.group.GroupsCollection;
 import com.google.inject.Inject;
 import java.util.Arrays;
 import java.util.List;
@@ -48,8 +44,6 @@ import org.junit.Test;
 public class SuggestReviewersIT extends AbstractDaemonTest {
   @Inject private CreateGroup.Factory createGroupFactory;
 
-  @Inject private GroupsCollection groups;
-
   private AccountGroup group1;
   private AccountGroup group2;
   private AccountGroup group3;
@@ -432,8 +426,7 @@ public class SuggestReviewersIT extends AbstractDaemonTest {
 
   private AccountGroup group(String name) throws Exception {
     GroupInfo group = createGroupFactory.create(name(name)).apply(TopLevelResource.INSTANCE, null);
-    GroupDescription.Basic d = groups.parseInternal(Url.decode(group.id));
+    return groupCache.get(new AccountGroup.UUID(group.id));
-    return GroupDescriptions.toAccountGroup(d);
   }
 
   private TestAccount user(String name, String fullName, String emailName, AccountGroup... groups)

gerrit-common/src/main/java/com/google/gerrit/common/data/GroupDescription.java

@@ -16,6 +16,7 @@ package com.google.gerrit.common.data;
 
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.reviewdb.client.AccountGroup;
+import java.sql.Timestamp;
 
 /** Group methods exposed by the GroupBackend. */
 public class GroupDescription {
@@ -42,10 +43,18 @@ public class GroupDescription {
     String getUrl();
   }
 
-  /** The extended information exposed by internal groups backed by an AccountGroup. */
+  /** The extended information exposed by internal groups. */
   public interface Internal extends Basic {
-    /** @return the backing AccountGroup. */
+
-    AccountGroup getAccountGroup();
+    AccountGroup.Id getId();
+
+    String getDescription();
+
+    AccountGroup.UUID getOwnerGroupUUID();
+
+    boolean isVisibleToAll();
+
+    Timestamp getCreatedOn();
   }
 
   private GroupDescription() {}

gerrit-common/src/main/java/com/google/gerrit/common/data/GroupDescriptions.java

@@ -17,18 +17,11 @@ package com.google.gerrit.common.data;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.PageLinks;
 import com.google.gerrit.reviewdb.client.AccountGroup;
+import java.sql.Timestamp;
 
 /** Utility class for building GroupDescription objects. */
 public class GroupDescriptions {
 
-  @Nullable
-  public static AccountGroup toAccountGroup(GroupDescription.Basic group) {
-    if (group instanceof GroupDescription.Internal) {
-      return ((GroupDescription.Internal) group).getAccountGroup();
-    }
-    return null;
-  }
-
   public static GroupDescription.Internal forAccountGroup(AccountGroup group) {
     return new GroupDescription.Internal() {
       @Override
@@ -41,11 +34,6 @@ public class GroupDescriptions {
         return group.getName();
       }
 
-      @Override
-      public AccountGroup getAccountGroup() {
-        return group;
-      }
-
       @Override
       @Nullable
       public String getEmailAddress() {
@@ -53,10 +41,34 @@ public class GroupDescriptions {
       }
 
       @Override
-      @Nullable
       public String getUrl() {
         return "#" + PageLinks.toGroup(getGroupUUID());
       }
+
+      @Override
+      public AccountGroup.Id getId() {
+        return group.getId();
+      }
+
+      @Override
+      public String getDescription() {
+        return group.getDescription();
+      }
+
+      @Override
+      public AccountGroup.UUID getOwnerGroupUUID() {
+        return group.getOwnerGroupUUID();
+      }
+
+      @Override
+      public boolean isVisibleToAll() {
+        return group.isVisibleToAll();
+      }
+
+      @Override
+      public Timestamp getCreatedOn() {
+        return group.getCreatedOn();
+      }
     };
   }
 

gerrit-common/src/main/java/com/google/gerrit/common/data/GroupInfo.java

@@ -46,8 +46,7 @@ public class GroupInfo {
     url = a.getUrl();
 
     if (a instanceof GroupDescription.Internal) {
-      AccountGroup group = ((GroupDescription.Internal) a).getAccountGroup();
+      description = ((GroupDescription.Internal) a).getDescription();
-      description = group.getDescription();
     }
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/account/CreateAccount.java

@@ -18,7 +18,7 @@ import static com.google.gerrit.server.account.externalids.ExternalId.SCHEME_MAI
 
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.GlobalCapability;
-import com.google.gerrit.common.data.GroupDescriptions;
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.InvalidSshKeyException;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.annotations.RequiresCapability;
@@ -211,8 +211,8 @@ public class CreateAccount implements RestModifyView<TopLevelResource, AccountIn
     Set<AccountGroup.UUID> groupUuids = new HashSet<>();
     if (groups != null) {
       for (String g : groups) {
-        AccountGroup group = GroupDescriptions.toAccountGroup(groupsCollection.parseInternal(g));
+        GroupDescription.Internal internalGroup = groupsCollection.parseInternal(g);
-        groupUuids.add(group.getGroupUUID());
+        groupUuids.add(internalGroup.getGroupUUID());
       }
     }
     return groupUuids;

gerrit-server/src/main/java/com/google/gerrit/server/account/GroupControl.java

@@ -142,12 +142,15 @@ public class GroupControl {
   }
 
   public boolean isOwner() {
-    AccountGroup accountGroup = GroupDescriptions.toAccountGroup(group);
+    if (isOwner != null) {
-    if (accountGroup == null) {
+      return isOwner;
-      isOwner = false;
+    }
-    } else if (isOwner == null) {
+
-      AccountGroup.UUID ownerUUID = accountGroup.getOwnerGroupUUID();
+    if (group instanceof GroupDescription.Internal) {
+      AccountGroup.UUID ownerUUID = ((GroupDescription.Internal) group).getOwnerGroupUUID();
       isOwner = getUser().getEffectiveGroups().contains(ownerUUID) || canAdministrateServer();
+    } else {
+      isOwner = false;
     }
     return isOwner;
   }
@@ -189,7 +192,9 @@ public class GroupControl {
   }
 
   private boolean canSeeMembers() {
-    AccountGroup accountGroup = GroupDescriptions.toAccountGroup(group);
+    if (group instanceof GroupDescription.Internal) {
-    return (accountGroup != null && accountGroup.isVisibleToAll()) || isOwner();
+      return ((GroupDescription.Internal) group).isVisibleToAll() || isOwner();
+    }
+    return false;
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/account/InternalGroupBackend.java

@@ -85,6 +85,6 @@ public class InternalGroupBackend implements GroupBackend {
   @Override
   public boolean isVisibleToAll(AccountGroup.UUID uuid) {
     GroupDescription.Internal g = get(uuid);
-    return g != null && g.getAccountGroup().isVisibleToAll();
+    return g != null && g.isVisibleToAll();
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/group/AddIncludedGroups.java

@@ -87,10 +87,8 @@ public class AddIncludedGroups implements RestModifyView<GroupResource, Input> {
   public List<GroupInfo> apply(GroupResource resource, Input input)
       throws MethodNotAllowedException, AuthException, UnprocessableEntityException, OrmException,
           ResourceNotFoundException {
-    AccountGroup group = resource.toAccountGroup();
+    GroupDescription.Internal group =
-    if (group == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
     input = Input.init(input);
 
     GroupControl control = resource.getControl();

gerrit-server/src/main/java/com/google/gerrit/server/group/AddMembers.java

@@ -17,6 +17,7 @@ package com.google.gerrit.server.group;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.client.AuthType;
 import com.google.gerrit.extensions.common.AccountInfo;
@@ -111,10 +112,8 @@ public class AddMembers implements RestModifyView<GroupResource, Input> {
   public List<AccountInfo> apply(GroupResource resource, Input input)
       throws AuthException, MethodNotAllowedException, UnprocessableEntityException, OrmException,
           IOException, ConfigInvalidException, ResourceNotFoundException {
-    AccountGroup internalGroup = resource.toAccountGroup();
+    GroupDescription.Internal internalGroup =
-    if (internalGroup == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
     input = Input.init(input);
 
     GroupControl control = resource.getControl();

gerrit-server/src/main/java/com/google/gerrit/server/group/CreateGroup.java

@@ -166,8 +166,8 @@ public class CreateGroup implements RestModifyView<TopLevelResource, GroupInput>
 
   private AccountGroup.Id owner(GroupInput input) throws UnprocessableEntityException {
     if (input.ownerId != null) {
-      GroupDescription.Basic d = groups.parseInternal(Url.decode(input.ownerId));
+      GroupDescription.Internal d = groups.parseInternal(Url.decode(input.ownerId));
-      return GroupDescriptions.toAccountGroup(d).getId();
+      return d.getId();
     }
     return null;
   }

gerrit-server/src/main/java/com/google/gerrit/server/group/DeleteIncludedGroups.java

@@ -54,10 +54,8 @@ public class DeleteIncludedGroups implements RestModifyView<GroupResource, Input
   public Response<?> apply(GroupResource resource, Input input)
       throws AuthException, MethodNotAllowedException, UnprocessableEntityException, OrmException,
           ResourceNotFoundException {
-    AccountGroup internalGroup = resource.toAccountGroup();
+    GroupDescription.Internal internalGroup =
-    if (internalGroup == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
     input = Input.init(input);
 
     final GroupControl control = resource.getControl();

gerrit-server/src/main/java/com/google/gerrit/server/group/DeleteMembers.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.group;
 
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
@@ -56,10 +57,8 @@ public class DeleteMembers implements RestModifyView<GroupResource, Input> {
   public Response<?> apply(GroupResource resource, Input input)
       throws AuthException, MethodNotAllowedException, UnprocessableEntityException, OrmException,
           IOException, ConfigInvalidException, ResourceNotFoundException {
-    AccountGroup internalGroup = resource.toAccountGroup();
+    GroupDescription.Internal internalGroup =
-    if (internalGroup == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
     input = Input.init(input);
 
     final GroupControl control = resource.getControl();

gerrit-server/src/main/java/com/google/gerrit/server/group/GetAuditLog.java

@@ -64,10 +64,9 @@ public class GetAuditLog implements RestReadView<GroupResource> {
   @Override
   public List<? extends GroupAuditEventInfo> apply(GroupResource rsrc)
       throws AuthException, MethodNotAllowedException, OrmException {
-    AccountGroup group = rsrc.toAccountGroup();
+    GroupDescription.Internal group =
-    if (group == null) {
+        rsrc.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
+    if (!rsrc.getControl().isOwner()) {
-    } else if (!rsrc.getControl().isOwner()) {
       throw new AuthException("Not group owner");
     }
 

gerrit-server/src/main/java/com/google/gerrit/server/group/GetDescription.java

@@ -15,19 +15,17 @@
 package com.google.gerrit.server.group;
 
 import com.google.common.base.Strings;
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.RestReadView;
-import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.inject.Singleton;
 
 @Singleton
 public class GetDescription implements RestReadView<GroupResource> {
   @Override
   public String apply(GroupResource resource) throws MethodNotAllowedException {
-    AccountGroup group = resource.toAccountGroup();
+    GroupDescription.Internal group =
-    if (group == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
     return Strings.nullToEmpty(group.getDescription());
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/group/GetOwner.java

@@ -14,12 +14,12 @@
 
 package com.google.gerrit.server.group;
 
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.common.GroupInfo;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestReadView;
-import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.server.account.GroupControl;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -40,10 +40,8 @@ public class GetOwner implements RestReadView<GroupResource> {
   @Override
   public GroupInfo apply(GroupResource resource)
       throws MethodNotAllowedException, ResourceNotFoundException, OrmException {
-    AccountGroup group = resource.toAccountGroup();
+    GroupDescription.Internal group =
-    if (group == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
     try {
       GroupControl c = controlFactory.validateFor(group.getOwnerGroupUUID());
       return json.format(c.getGroup());

gerrit-server/src/main/java/com/google/gerrit/server/group/GroupJson.java

@@ -19,7 +19,6 @@ import static com.google.gerrit.extensions.client.ListGroupsOption.MEMBERS;
 
 import com.google.common.base.Strings;
 import com.google.gerrit.common.data.GroupDescription;
-import com.google.gerrit.common.data.GroupDescriptions;
 import com.google.gerrit.extensions.client.ListGroupsOption;
 import com.google.gerrit.extensions.common.GroupInfo;
 import com.google.gerrit.extensions.common.GroupOptionsInfo;
@@ -37,8 +36,7 @@ import java.util.EnumSet;
 public class GroupJson {
   public static GroupOptionsInfo createOptions(GroupDescription.Basic group) {
     GroupOptionsInfo options = new GroupOptionsInfo();
-    AccountGroup ag = GroupDescriptions.toAccountGroup(group);
+    if (isInternalGroup(group) && ((GroupDescription.Internal) group).isVisibleToAll()) {
-    if (ag != null && ag.isVisibleToAll()) {
       options.visibleToAll = true;
     }
     return options;
@@ -96,25 +94,30 @@ public class GroupJson {
     info.url = Strings.emptyToNull(group.getUrl());
     info.options = createOptions(group);
 
-    AccountGroup g = GroupDescriptions.toAccountGroup(group);
+    if (isInternalGroup(group)) {
-    if (g != null) {
+      GroupDescription.Internal internalGroup = (GroupDescription.Internal) group;
-      info.description = Strings.emptyToNull(g.getDescription());
+      info.description = Strings.emptyToNull(internalGroup.getDescription());
-      info.groupId = g.getId().get();
+      info.groupId = internalGroup.getId().get();
-      if (g.getOwnerGroupUUID() != null) {
+      AccountGroup.UUID ownerGroupUUID = internalGroup.getOwnerGroupUUID();
-        info.ownerId = Url.encode(g.getOwnerGroupUUID().get());
+      if (ownerGroupUUID != null) {
-        GroupDescription.Basic o = groupBackend.get(g.getOwnerGroupUUID());
+        info.ownerId = Url.encode(ownerGroupUUID.get());
+        GroupDescription.Basic o = groupBackend.get(ownerGroupUUID);
         if (o != null) {
           info.owner = o.getName();
         }
       }
-      info.createdOn = g.getCreatedOn();
+      info.createdOn = internalGroup.getCreatedOn();
     }
 
     return info;
   }
 
+  private static boolean isInternalGroup(GroupDescription.Basic group) {
+    return group instanceof GroupDescription.Internal;
+  }
+
   private GroupInfo initMembersAndIncludes(GroupResource rsrc, GroupInfo info) throws OrmException {
-    if (rsrc.toAccountGroup() == null) {
+    if (!rsrc.isInternalGroup()) {
       return info;
     }
     try {

gerrit-server/src/main/java/com/google/gerrit/server/group/GroupResource.java

@@ -15,12 +15,11 @@
 package com.google.gerrit.server.group;
 
 import com.google.gerrit.common.data.GroupDescription;
-import com.google.gerrit.common.data.GroupDescriptions;
 import com.google.gerrit.extensions.restapi.RestResource;
 import com.google.gerrit.extensions.restapi.RestView;
-import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.server.account.GroupControl;
 import com.google.inject.TypeLiteral;
+import java.util.Optional;
 
 public class GroupResource implements RestResource {
   public static final TypeLiteral<RestView<GroupResource>> GROUP_KIND =
@@ -44,12 +43,17 @@ public class GroupResource implements RestResource {
     return getGroup().getName();
   }
 
-  public AccountGroup.UUID getGroupUUID() {
+  public boolean isInternalGroup() {
-    return getGroup().getGroupUUID();
+    GroupDescription.Basic group = getGroup();
+    return group instanceof GroupDescription.Internal;
   }
 
-  public AccountGroup toAccountGroup() {
+  public Optional<GroupDescription.Internal> asInternalGroup() {
-    return GroupDescriptions.toAccountGroup(getGroup());
+    GroupDescription.Basic group = getGroup();
+    if (group instanceof GroupDescription.Internal) {
+      return Optional.of((GroupDescription.Internal) group);
+    }
+    return Optional.empty();
   }
 
   public GroupControl getControl() {

gerrit-server/src/main/java/com/google/gerrit/server/group/GroupsCollection.java

@@ -16,7 +16,6 @@ package com.google.gerrit.server.group;
 
 import com.google.common.collect.ListMultimap;
 import com.google.gerrit.common.data.GroupDescription;
-import com.google.gerrit.common.data.GroupDescriptions;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.registration.DynamicMap;
@@ -142,12 +141,13 @@ public class GroupsCollection
    * @throws UnprocessableEntityException thrown if the group ID cannot be resolved, if the group is
    *     not visible to the calling user or if it's an external group
    */
-  public GroupDescription.Basic parseInternal(String id) throws UnprocessableEntityException {
+  public GroupDescription.Internal parseInternal(String id) throws UnprocessableEntityException {
     GroupDescription.Basic group = parse(id);
-    if (GroupDescriptions.toAccountGroup(group) == null) {
+    if (group instanceof GroupDescription.Internal) {
-      throw new UnprocessableEntityException(String.format("External Group Not Allowed: %s", id));
+      return (GroupDescription.Internal) group;
     }
-    return group;
+
+    throw new UnprocessableEntityException(String.format("External Group Not Allowed: %s", id));
   }
 
   /**

gerrit-server/src/main/java/com/google/gerrit/server/group/IncludedGroupsCollection.java

@@ -25,7 +25,6 @@ import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
-import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.group.AddIncludedGroups.PutIncludedGroup;
 import com.google.gwtorm.server.OrmException;
@@ -67,10 +66,8 @@ public class IncludedGroupsCollection
   @Override
   public IncludedGroupResource parse(GroupResource resource, IdString id)
       throws MethodNotAllowedException, AuthException, ResourceNotFoundException, OrmException {
-    AccountGroup parent = resource.toAccountGroup();
+    GroupDescription.Internal parent =
-    if (parent == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
 
     GroupDescription.Basic member =
         groupsCollection.parse(TopLevelResource.INSTANCE, id).getGroup();
@@ -80,7 +77,7 @@ public class IncludedGroupsCollection
     throw new ResourceNotFoundException(id);
   }
 
-  private boolean isMember(AccountGroup parent, GroupDescription.Basic member)
+  private boolean isMember(GroupDescription.Internal parent, GroupDescription.Basic member)
       throws OrmException, ResourceNotFoundException {
     try {
       return groups.isIncluded(dbProvider.get(), parent.getGroupUUID(), member.getGroupUUID());

gerrit-server/src/main/java/com/google/gerrit/server/group/Index.java

@@ -14,7 +14,6 @@
 
 package com.google.gerrit.server.group;
 
-import com.google.gerrit.common.data.GroupDescriptions;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestModifyView;
@@ -44,14 +43,15 @@ public class Index implements RestModifyView<GroupResource, Input> {
       throw new AuthException("not allowed to index group");
     }
 
-    AccountGroup group = GroupDescriptions.toAccountGroup(rsrc.getGroup());
+    AccountGroup.UUID groupUuid = rsrc.getGroup().getGroupUUID();
-    if (group == null) {
+    if (!rsrc.isInternalGroup()) {
       throw new UnprocessableEntityException(
-          String.format("External Group Not Allowed: %s", rsrc.getGroupUUID().get()));
+          String.format("External Group Not Allowed: %s", groupUuid.get()));
     }
 
+    AccountGroup accountGroup = groupCache.get(groupUuid);
     // evicting the group from the cache, reindexes the group
-    groupCache.evict(group);
+    groupCache.evict(accountGroup);
     return Response.none();
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/group/ListIncludedGroups.java

@@ -16,6 +16,7 @@ package com.google.gerrit.server.group;
 
 import static com.google.common.base.Strings.nullToEmpty;
 
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.common.GroupInfo;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
@@ -51,14 +52,13 @@ public class ListIncludedGroups implements RestReadView<GroupResource> {
 
   @Override
   public List<GroupInfo> apply(GroupResource rsrc) throws MethodNotAllowedException, OrmException {
-    if (rsrc.toAccountGroup() == null) {
+    GroupDescription.Internal group =
-      throw new MethodNotAllowedException();
+        rsrc.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-    }
 
     boolean ownerOfParent = rsrc.getControl().isOwner();
     List<GroupInfo> included = new ArrayList<>();
     Collection<AccountGroup.UUID> includedGroupUuids =
-        groupIncludeCache.subgroupsOf(rsrc.toAccountGroup().getGroupUUID());
+        groupIncludeCache.subgroupsOf(group.getGroupUUID());
     for (AccountGroup.UUID includedGroupUuid : includedGroupUuids) {
       try {
         GroupControl i = controlFactory.controlFor(includedGroupUuid);
@@ -69,7 +69,7 @@ public class ListIncludedGroups implements RestReadView<GroupResource> {
         log.warn(
             String.format(
                 "Group %s no longer available, included into %s",
-                includedGroupUuid, rsrc.getGroup().getName()));
+                includedGroupUuid, group.getName()));
         continue;
       }
     }

gerrit-server/src/main/java/com/google/gerrit/server/group/ListMembers.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.group;
 
 import com.google.common.collect.Lists;
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.data.GroupDetail;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.common.AccountInfo;
@@ -61,11 +62,9 @@ public class ListMembers implements RestReadView<GroupResource> {
   @Override
   public List<AccountInfo> apply(GroupResource resource)
       throws MethodNotAllowedException, OrmException {
-    if (resource.toAccountGroup() == null) {
+    GroupDescription.Internal group =
-      throw new MethodNotAllowedException();
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-    }
+    return apply(group.getGroupUUID());
-
-    return apply(resource.getGroupUUID());
   }
 
   public List<AccountInfo> apply(AccountGroup group) throws OrmException {

gerrit-server/src/main/java/com/google/gerrit/server/group/MembersCollection.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.group;
 
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsCreate;
@@ -71,10 +72,8 @@ public class MembersCollection
   public MemberResource parse(GroupResource parent, IdString id)
       throws MethodNotAllowedException, AuthException, ResourceNotFoundException, OrmException,
           IOException, ConfigInvalidException {
-    AccountGroup group = parent.toAccountGroup();
+    GroupDescription.Internal group =
-    if (group == null) {
+        parent.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
-    }
 
     IdentifiedUser user = accounts.parse(TopLevelResource.INSTANCE, id).getUser();
     if (parent.getControl().canSeeMember(user.getAccountId()) && isMember(group, user)) {
@@ -83,7 +82,7 @@ public class MembersCollection
     throw new ResourceNotFoundException(id);
   }
 
-  private boolean isMember(AccountGroup group, IdentifiedUser user)
+  private boolean isMember(GroupDescription.Internal group, IdentifiedUser user)
       throws OrmException, ResourceNotFoundException {
     AccountGroup.UUID groupUuid = group.getGroupUUID();
     try {

gerrit-server/src/main/java/com/google/gerrit/server/group/PutDescription.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.group;
 
 import com.google.common.base.Strings;
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.DefaultInput;
@@ -56,16 +57,15 @@ public class PutDescription implements RestModifyView<GroupResource, Input> {
       input = new Input(); // Delete would set description to null.
     }
 
-    AccountGroup accountGroup = resource.toAccountGroup();
+    GroupDescription.Internal internalGroup =
-    if (accountGroup == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
+    if (!resource.getControl().isOwner()) {
-    } else if (!resource.getControl().isOwner()) {
       throw new AuthException("Not group owner");
     }
 
     String newDescription = Strings.emptyToNull(input.description);
-    if (!Objects.equals(accountGroup.getDescription(), newDescription)) {
+    if (!Objects.equals(internalGroup.getDescription(), newDescription)) {
-      AccountGroup.UUID groupUuid = resource.getGroupUUID();
+      AccountGroup.UUID groupUuid = internalGroup.getGroupUUID();
       try {
         groupsUpdateProvider
             .get()

gerrit-server/src/main/java/com/google/gerrit/server/group/PutName.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.group;
 
 import com.google.common.base.Strings;
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NameAlreadyUsedException;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.restapi.AuthException;
@@ -52,9 +53,9 @@ public class PutName implements RestModifyView<GroupResource, Input> {
   public String apply(GroupResource rsrc, Input input)
       throws MethodNotAllowedException, AuthException, BadRequestException,
           ResourceConflictException, ResourceNotFoundException, OrmException, IOException {
-    if (rsrc.toAccountGroup() == null) {
+    GroupDescription.Internal internalGroup =
-      throw new MethodNotAllowedException();
+        rsrc.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-    } else if (!rsrc.getControl().isOwner()) {
+    if (!rsrc.getControl().isOwner()) {
       throw new AuthException("Not group owner");
     } else if (input == null || Strings.isNullOrEmpty(input.name)) {
       throw new BadRequestException("name is required");
@@ -64,15 +65,15 @@ public class PutName implements RestModifyView<GroupResource, Input> {
       throw new BadRequestException("name is required");
     }
 
-    if (rsrc.toAccountGroup().getName().equals(newName)) {
+    if (internalGroup.getName().equals(newName)) {
       return newName;
     }
 
-    renameGroup(rsrc.toAccountGroup(), newName);
+    renameGroup(internalGroup, newName);
     return newName;
   }
 
-  private void renameGroup(AccountGroup group, String newName)
+  private void renameGroup(GroupDescription.Internal group, String newName)
       throws ResourceConflictException, ResourceNotFoundException, OrmException, IOException {
     AccountGroup.UUID groupUuid = group.getGroupUUID();
     try {

gerrit-server/src/main/java/com/google/gerrit/server/group/PutOptions.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.group;
 
+import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.common.GroupOptionsInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
@@ -44,10 +45,9 @@ public class PutOptions implements RestModifyView<GroupResource, GroupOptionsInf
   public GroupOptionsInfo apply(GroupResource resource, GroupOptionsInfo input)
       throws MethodNotAllowedException, AuthException, BadRequestException,
           ResourceNotFoundException, OrmException, IOException {
-    AccountGroup accountGroup = resource.toAccountGroup();
+    GroupDescription.Internal internalGroup =
-    if (accountGroup == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
+    if (!resource.getControl().isOwner()) {
-    } else if (!resource.getControl().isOwner()) {
       throw new AuthException("Not group owner");
     }
 
@@ -58,8 +58,8 @@ public class PutOptions implements RestModifyView<GroupResource, GroupOptionsInf
       input.visibleToAll = false;
     }
 
-    if (accountGroup.isVisibleToAll() != input.visibleToAll) {
+    if (internalGroup.isVisibleToAll() != input.visibleToAll) {
-      AccountGroup.UUID groupUuid = accountGroup.getGroupUUID();
+      AccountGroup.UUID groupUuid = internalGroup.getGroupUUID();
       try {
         groupsUpdateProvider
             .get()

gerrit-server/src/main/java/com/google/gerrit/server/group/PutOwner.java

@@ -61,10 +61,9 @@ public class PutOwner implements RestModifyView<GroupResource, Input> {
   public GroupInfo apply(GroupResource resource, Input input)
       throws ResourceNotFoundException, MethodNotAllowedException, AuthException,
           BadRequestException, UnprocessableEntityException, OrmException, IOException {
-    AccountGroup accountGroup = resource.toAccountGroup();
+    GroupDescription.Internal internalGroup =
-    if (accountGroup == null) {
+        resource.asInternalGroup().orElseThrow(MethodNotAllowedException::new);
-      throw new MethodNotAllowedException();
+    if (!resource.getControl().isOwner()) {
-    } else if (!resource.getControl().isOwner()) {
       throw new AuthException("Not group owner");
     }
 
@@ -73,8 +72,8 @@ public class PutOwner implements RestModifyView<GroupResource, Input> {
     }
 
     GroupDescription.Basic owner = groupsCollection.parse(input.owner);
-    if (!accountGroup.getOwnerGroupUUID().equals(owner.getGroupUUID())) {
+    if (!internalGroup.getOwnerGroupUUID().equals(owner.getGroupUUID())) {
-      AccountGroup.UUID groupUuid = resource.getGroupUUID();
+      AccountGroup.UUID groupUuid = internalGroup.getGroupUUID();
       try {
         groupsUpdateProvider
             .get()

gerrit-server/src/main/java/com/google/gerrit/server/mail/send/ProjectWatch.java

@@ -16,7 +16,6 @@ package com.google.gerrit.server.mail.send;
 
 import com.google.common.base.Strings;
 import com.google.gerrit.common.data.GroupDescription;
-import com.google.gerrit.common.data.GroupDescriptions;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.index.query.Predicate;
@@ -175,12 +174,12 @@ public class ProjectWatch {
         continue;
       }
 
-      AccountGroup ig = GroupDescriptions.toAccountGroup(group);
+      if (!(group instanceof GroupDescription.Internal)) {
-      if (ig == null) {
         // Non-internal groups cannot be expanded by the server.
         continue;
       }
 
+      GroupDescription.Internal ig = (GroupDescription.Internal) group;
       try {
         args.groups.getMembers(db, ig.getGroupUUID()).forEach(matching.accounts::add);
       } catch (NoSuchGroupException e) {